In the analysis instruments and topography systems known from the prior art, an eye is generally illuminated with monochromatic light, such as infrared light for example, so as to avoid dazzling the person or subject to be examined where possible. Topography systems are thus known which, in addition to measuring a surface of an eye, also enable pupillometric measurements. In particular when the eye is illuminated with monochromatic light, which is only partly visible, a contraction of the pupil is effectively prevented, and therefore an illumination of this type is particularly well suited for pupillometric measurements. Topography systems may, however, also have a plurality of light colours for illumination of an eye. For example, Placido rings are then projected onto the eye in different monochromatic light colours. This is basically used for distinction of the rings of the image pattern imaged on the eye and for the sole purpose of determining a topography. Placido rings of this type in different monochromatic light colours consequently form the first light source alone. It is further known to examine meibomian glands under infrared light.
Analysis instruments for measuring topography or what are known as “keratometers” can also be used for non-invasive analysis of a tear film on an eye. The image pattern projected onto the surface of the eye is recorded substantially continuously, wherein any break-up in the tear film can be identified by a change to the image pattern. In order to establish the quality of the tear film, a break-up time thereof is generally measured. This measurement is likewise carried out by illuminating the eye with infrared light. For example, in addition to the topography of the surface of the eye, a measurement of a tear film is also of utmost importance when selecting contact lenses. Furthermore, analysis of a tear film is limited merely to a distribution of the tear film over the eye. A disadvantage of the known analysis instrument and method is that the possibilities for examining an eye are limited. It is therefore desirable to broaden the examination possibilities of an instrument of this type so as to obtain further and more detailed measurement results where necessary, which can be used for example for improved contact lens selection and fitting.